This invention relates to a level indicating device and, more specifically, to a device for locating points in the same horizontal plane by measuring up or down from a reference plane as determined by the level of liquid in an elongated tubing when moved to various locations.
Liquid level has long been employed as a medium for determining points in a single plane, and devices including a reservoir and a length of hose in communication therewith have previously been employed for that purpose. However, such devices generally require at least two people in order to operate them effectively, or they require that the container be set up or installed on a fixed platform or base. In Opazo U.S. Pat. No. 4,356,639, hydrostatic pressure of water in a portable tank is transmitted by hose to a pressure transducer where a difference in height represented by the different pressure is measured. The patent states that the invention requires a topographer and an assistant for transport of the portable tank and the hose.
In From U.S. Pat. No. 4,375,765, a large container at one end of the hose must be placed on a flat, stable surface while the other end is used to establish a horizontal plane.
In Gauthier U.S. Pat. No. 4,422,244, a reservoir is supported on a fixed base and elevations are read at different locations by the level of fluid in the end of the tube relative to the ground level.